Switches for use in RF circuits generally comprise variously arranged diodes which act to switch the RF transmission lines between two or more states. For instance, the diodes may couple and decouple loading stubs to a transmission line to cause a phase shift thereon. Each diode requires control, or bias lines coupled to it to provide the switching commands. Such diode switches are commonly used, for example, to construct digitally controlled phase-shifters for use in phased array antennas and the like.
However, when a large number of diode RF switches are arrayed, such as in the case in a phased array antenna, the grid of control wires necessary to control each of the phase shifters substantially increases the RCS of the overall structure. Thus, a phased array antenna of this type has a relatively high RCS even at frequencies substantially lower than those at which the antenna operates.
Mechanical RF switches known in prior art are generally not low RCS devices and are also unsuited for use in phased arrays because of their extremely low switching speeds.